Method for unwinding a bobbin of a coiled sheet and kit to unwind a sheet of material wound in a bobbin

Abstract

The present invention relates to a method for unwinding a bobbin (12) of a coiled sheet (13), the method comprising the steps of: providing a bobbin of a coiled sheet, the bobbin having a first rotation axis (17) and comprising a free portion (14) of the sheet unwound from the bobbin, the free portion (14) defining a contact line (16) as a line separating the free portion and the remaining of the coiled sheet (13); providing a roller (30) having a second rotation axis substantially parallel to the first rotation axis (17); putting the roller (30) in contact with the bobbin (12) at the contact line (16); unwinding the sheet from the bobbin (12) pulling the sheet in an unwinding direction such that an angle between the free portion of the sheet and a radius of the bobbin at the contact line is comprised between about 110 degrees and about 150 degrees or between about 200 degrees and about 300 degrees; and while unwinding the sheet from the bobbin keeping the roller in contact with the outer surface of the bobbin. The present invention also relates to a kit to unwind a sheet of material wound in a bobbin.

The invention claimed is: 
     
       1. A method for unwinding a bobbin of a coiled sheet including a homogenized tobacco sheet, the method comprising the steps of:
 providing a bobbin of a coiled sheet including a sheet of a material comprising a homogenized tobacco sheet, the bobbin having a first rotation axis and comprising a free portion of the sheet unwound from the bobbin, the free portion defining a contact line as a line separating the free portion and the remaining of the coiled sheet; 
 providing a roller having a second rotation axis substantially parallel to the first rotation axis; 
 putting the roller in contact with the bobbin at the contact line; 
 unwinding the sheet from the bobbin pulling the sheet in an unwinding direction such that an angle between the free portion of the sheet and a radius of the bobbin at the contact line is comprised between about 110 degrees and about 150 degrees or between about 200 degrees and about 300 degrees; 
 while unwinding the sheet from the bobbin, keeping the roller in contact with an outer surface of the bobbin. 
 
     
     
       2. The method according to  claim 1 , wherein the roller moves its angular position with respect of the bobbin while unwinding. 
     
     
       3. The method according to  claim 1 , including rotating the roller in a direction opposite to a rotation direction of the bobbin during unwinding. 
     
     
       4. The method according to  claim 1 , including placing the free portion of the sheet in contact with the roller for a length equal to at least about 40% of a perimeter of the roller. 
     
     
       5. The method according to  claim 1 , including arranging a scraper between the free portion of the sheet and the remaining of the sheet coiled in the bobbin in such a way that the scraper is in contact with the sheet coiled in the bobbin. 
     
     
       6. The method according to  claim 1 , including:
 determining a roundness of the bobbin; 
 selecting an unwinding velocity of the bobbin based on the determined roundness. 
 
     
     
       7. The method according to  claim 1 , including sensing a diameter of the bobbin. 
     
     
       8. A kit to unwind a sheet of material wound in a bobbin, the kit comprising:
 a bobbin of a coiled sheet including a homogenized tobacco sheet defining an outer surface and a free portion of the sheet unwound from the bobbin, the free portion defining a contact line as a line separating the free portion and the remaining of the coiled sheet; 
 an apparatus including:
 a bobbin holder holding the bobbin rotatable around a first axis; 
 a roller having a second rotation axis substantially parallel to the first rotation axis, the roller being in contact with the outer surface of the bobbin at the contact line; 
 a pulling device adapted to pull the free portion of the sheet of the bobbin along an unwinding direction; 
 wherein the roller and the pulling device are respectively positioned so that an angle between the free portion of the sheet along the unwinding direction and a radius of the bobbin at the contact line is comprised between about 110 degrees and about 150 degrees or between about 200 degrees and about 300 degrees. 
 
 
     
     
       9. The kit according to  claim 8 , wherein the roller is arranged in a angularly movable position with respect of the holder. 
     
     
       10. The kit according to  claim 8 , wherein the apparatus includes a scraper arranged between the free portion of the sheet and the remaining of the sheet coiled in the bobbin in such a way that the scraper is in contact with the sheet coiled in the bobbin. 
     
     
       11. The kit according to  claim 8 , wherein the apparatus includes a speed regulator to vary a rotation speed around the first axis of the bobbin holder. 
     
     
       12. The kit according to  claim 8 , wherein the apparatus includes a diameter sensor to determine the diameter of the bobbin.